The present state of the market place for custom arch supports is primarily physician, podiatrist, and chiropractor driven. Initially, an ink pressure plate foot imprint, or a negative cast is made from the patient's foot. The imprint or cast is then sent to an orthotic fabricating laboratory for fabrication. Fabrication is done through multiple time consuming and labor intensive processes that can be cost prohibitive. However, there are several companies that have developed computerized systems for fabricating orthotics, but these companies market primarily to physicians. The one company that is able to mill an orthotic, ADT, must take the negative cast that has been mailed to them by the doctor, and using a wand digitizer, digitize and then manipulate the image and then mill the device on a large mill that is housed in a warehouse.
The foot acts as a platform to support the human body. But the foot is more than just a flat board on which our body weight is supported. The foot is an intricate appendage that consists of twenty-six bones, as well as multiple joints, ligaments, muscles, nerves and vessels. The foot must be able to function in a smooth balanced systematic way, or it starts to become painful and deformities can develop. Additionally, the foot is a dynamic structure that changes as our weight is applied in a non-uniform fashion. As the body's center of gravity moves over the foot, the arch must lower and the foot becomes a flexible structure adapting to changes in the surface of the terrain upon which the feet are walking. Man has not always worn shoes and walked on paved surfaces, which may be contributing to the many foot problems modern man is suffering today. When the body weight is directly over the single supporting boot during a stride, the boot must change its function from a flexible structure to a rigid structure so that our body weight can move from the whole foot bearing the weight to only the ball of the foot and toe area, which is the area bearing the body weight as we push off to the next step.
In normal walking the foot acts as a complicated musculoskeletal appendage upon which may ground reactive forces act. For example, at heel strike the vertical forces peak, and forward shear, medial shear, and internal torque shear also occur. During the foot flat phase, vertical forces fore-aft shear, and internal-external shear decrease, while integral shear increases. During heel off, and the beginning of the propulsive phase of gait, vertical forces, aft shear, external shear, and medial shear increases to the forefoot area of the foot. Although this description is a simplified version of gait cycle, heal contact, foot flat, heel off and toe off, it is basically how the human foot functions. Abnormal function during the gait cycle helps to explain the many problems that over 40% of the human population that wear shoes experience.
The role of the arch support is to support the foot throughout the weight bearing part of the gait cycle and reduce abnormal stresses that can contribute to the ailments of the foot. Maximizing the functional control of the foot with the use of a foot support while reducing motion between the foot, the support and the shoe, will improve foot function, reduce the risk of developing deformity, and affectively slow down the progression of a deformity. Also, a support may help to prevent recurrence of deformity post-operatively. Additionally, there are may disease processes that can affect the foot leading to severe foot deformities, loss of or diminished sensation to the feet, as well as affecting other vital structures of the foot. For example, diabetes mellitus can cause a profound loss of the ability of a person to perceive pain. Subsequently the person may develop deformities of the foot medically termed Charcot Foot. The severely deformed foot will no longer have a bottom or plantar surface of the foot that resembles anything like a normal human foot. This deformed foot usually develops abnormal prominence on the plantar or weight bearing surface of the foot. These areas of abnormal prominence are areas of the foot that are subject to increased vertical and shearing forces and increased pressure. Increased localized pressure and the loss of the ability to feel pain have been implicated in the development of foot ulcers that can progress to infection, gangrene and loss of limb by amputation.
During many athletic activities the human foot has been determined to sustain an increase between 250-500% of the body weight. The increase in the forces going through the foot that is not functioning properly can damage the foot by causing acute injuries increasing the risk of developing deformities, and contributing to musculeskeletal problems of other areas though out the lower extremities and the lower back. By supporting the foot and aiding its function, many injuries associated with athletic activities can be reduced or prevented. Additionally, a foot support that can efficiently aid in foot function may not only prevent injuries to the foot or lower extremities, but may improve an individual's performance in the sport. In-most sports the human foot absorbs approximately 250-500% of the body weight, thus people who participate in sports will benefit from a properly designed foot support.